1. Field of the Invention
This invention is related to motor speed and torque controllers for both positive and negative torques, and to motor starters, and power output controllers. This invention is related to such controllers for brush-type and brushless machines, and more particularly, to controllers for brush-type and brushless electrical machines of the types disclosed in the referenced patents. This invention is related to controllers of conventional, brush-type and brushless motors in groups of two or more.
2. Background Art
Previous brush-type electrical machine controllers have used series resistance to control speed and torque and current, especially the excessive currents caused during the starting of series motors. The control of these brush-type machines is very important in considering the application of these motors. There has been a lack of a reliably-operating, efficient controller for brush-type machines. The speed and torque of a series motor energized from a constant potential supply can be controlled by inserting resistance in series with the supply line. Speed control for shunt and compound motors can be obtained by inserting resistance in series with the armature circuit only. The stator field flux of shunt motors can be varied to control the speed of these motors, although special care is required to prevent overspeeding of the motor if the shunt stator field flux becomes very weak. The speed of DC motors can be varied by varying the voltage applied to the motors; the Ward Leonard system of speed control is an example of varying the voltage applied to the DC motor. In the Ward Leonard system the adjustable output voltage from a motor-generator set is applied to the motor. Electric vehicle motor controllers use semiconductor chopper controllers as well as electromechanical switches to connect resistors and batteries in various combinations to regulate electrical power input to the motor, which thereby control the motor output torque. Alternating current induction motors are being controlled for powering other electric vehicles.